反应详情

5.4 g (2.2 mmol) of 2-ethoxy-N-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ) are added to 4.1 g (2 mmol) of tert-butoxycarbonyl-L-serine, 4.23 g (2 mmol) of D-glutamic acid dimethyl ester hydrochloride and 1.01 g (2 mmol) of N-methylmorpholine in 40 ml of dimethylformamide. After stirring for 16 hours at room temperature, the resulting suspension is filtered and the filtrate is evaporated to dryness. The oily residue is taken up in 150 ml of ethyl acetate and, in the cold, is washed 5 times with 50 ml of 2 N citric acid solution each time, then twice with 50 ml of water each time. The organic phase is dried, concentrated to approximately 40 ml and caused to crystallise by adding, in portions, 150 ml of ether/petroleum ether 2:1. 4.95 g (79%) of tert-butoxycarbonyl-L-seryl-D-glutamic acid dimethyl ester are obtained as colourless needles;

1. filtrationthe resulting suspension is filtered
2. customthe filtrate is evaporated to dryness
3. washin the cold, is washed 5 times with 50 ml of 2 N citric acid solution each time
4. customThe organic phase is dried
5. concentrationconcentrated to approximately 40 ml
6. customto crystallise
7. additionby adding, in portions, 150 ml of ether/petroleum ether 2:1